1. Field of the Invention
The invention relates to storage-stable silicone compositions and a process for their preparation.
2. Background Art
Silicone elastomers are well known products, and are generally prepared by the chain extension and/or crosslinking of reactive organopolysiloxane oligomers or polymers with or without low molecular weight crosslinkers. In many instances, it is desirable to provide a curable mixture or component thereof in viscous liquid or paste form. It is desirable that the consistency of such mixtures or components does not change during storage. As is known, the mechanical properties of silicone elastomers can be improved by addition of reinforcing fillers, such as e.g. silica or carbon black. Such additives have also been found to increase storage stability.
DE-3839900, for example, describes the use of prehydrophobized silica in silicone compositions. In contrast, EP 798342 describes the preparation of silicone compositions wherein hydrophilic silica is hydrophobized with silazanes in the presence of polysiloxanes and water. In both variants, the hydrophobization of silica improves the storage stability of the non-crosslinked silicone compositions. However, the storage stability is still inadequate.